Locomotive with bifurcated flues



first. 30, 1934. F, w $M|TH 1,978,822

LOCOMOTIVE WITH BIFURCATED FLUES Filed April 5, 1953 2 Sheets-Sheet l Iy\ L i- E' J INVENTQR F'ranK W. 3 mith.

d/kvu ATTORNEY Oct. 30, 1934. F. w. SMITH LOCOMOTIVE WITH BIFURCATEDFLUES Filed April 5, 1933 2 Sheets-Sheet 2 0 w Q xmwmw O owo Em DINVENTOR FranKW mLf h BY 01% ATTORNEY Patented Oct. 30, 1934 UNITEDSTATES PATENT OFFIQE Superheater Company,

New York, N. Y.

Application April 5, 1933, Serial No. 664,494

1 Claim.

My invention relates to boilers having horizontal fire tubes. In suchboilers serious deterioration of the tube sheets occurs at times causedby high metal temperature due to insuflicient circulation along thewetted faces of the sheets. Furthermore, a low water condition isparticularly serious in boilers having also an internal fire-box withcrown sheet, because the crown sheet may thereby be caused to becomeoverheated. Overheating of a crown sheet may require expensive repairsand it may also even cause the boiler to explode.

It is an object of my invention to provide an arrangement to increasethe water touched area of the hotter flue sheet of a horizontal firetube boiler having a given area of heating surface to thereby reduce theresistance to water circulation along such sheet and to increase thelife of such sheet by keeping it at a lower average temperature. Anotherobject of my invention is to provide an arrangement whereby the crownsheet of a boiler of the said type may be lowered and thereby theprobability of a low Water condition be decreased. Still another objectof my invention is to reduce the number of rolled joints in the fluesheets of a horizontal flre tube boiler.

In order that my invention, together with its objects and advantages,may be fully and readily understood, I will now describe in detail inconnection with the accompanying drawings and by way of example a boilerselected from a number of possible embodiments of my invention. In thedrawings,

Fig. 1 is a vertical sectional elevation of a locomotive in accordancewith my invention, parts being omitted.

Fig. 2 is a fragmentary section on a line 2-2 of Fig. 1. I

Fig. 3 is a fragmentary section on a line 3--3 looking in the directionof the arrows.

Fig. 4 is a fragmentary section on a line 4-4 of Fig. 2.

I have shown a locomotive having a barrel 10, a combustion chamber 12, acrown sheet 14 for said chamber and a smoke box 16.

Within the barrel 10 are a number of the ordinary fire tubes 18, 18 forconducting heating gases from the combustion space 12 to the smoke box16. At their rear ends, tubes 18 extend through and are rolled into thetube sheet 20. At their front ends the tubes 18 extend through and arerolled into tube sheet 22. It is customary at present to provide in thebarrel of a locomotive enlarged smoke tubes or flues 24,

24 adapted to receive superheater units 26, 26. Flues 24 also areadapted to conduct heating gases from chamber 12 to chamber 16 and haverolled joints in the sheets 20 and 22. Certain of the flues shown ashaving units 26 therein are, however, of the bifurcated type, such flueshaving unit receiving portions 24a connected in pairs to throats 24?)which are rolled into the sheet 20. The details of the bifurcated fluesseen in Figs. 1, 2 and 3, are best illustrated in Fig. 4. It will beseen that the cross-sectional area of the throats 2%, while each equalto the cross-sectional area of both the tubes 24a to which it connects,permit a greater ligament of metal between them than is provided betweenthe tubes 24 and that the throats 24b offer less resistance to the flowof water along the wetted surface of sheet 20 than would the flues 24avif such flues were extended through the sheet 20. The arrangement shownin Figs. 1, 2 and 3 therefore not only reduces the number of rolledjoints in sheet 20 but also permits a better water circulation incontact with such sheet to! both reduce the initial labor in assemblingthe flues and to prolong the life of the joints by maintaining the tubeends and tube sheet at a somewhat lower temperature. As illustrated, thepoints 28, 28 at which the throats 241) are bifurcated to form flues24a, or flues 24a united to form throats 2412 are adjacent the rear fluesheet 20. However, I do not limit myself in all cases to placing thebifurcation points near one or the other of the flue sheets.

As illustrated, the forward ends of flues 24a extend through the frontflue sheet directly from the points 28 so that the front flue sheet 22contains as many joints as though no bifurcated flues were employed.However, the use of bifurcations near the front flue sheet 22 isprohibited in the arrangement illustrated by the superheater units 26and I do not limit myself in all cases to the use of such units or tothe use of large flues. If the superheater units are omitted, all thefire tubes may be of the same size and they may all be bifurcated, orunited in pairs, at both. ends within my invention.

As best appears in Figs. 1 and 2 the throats 24b are offset so that theaxis of each throat 2422 comes more nearly in line with that of one ofthe flues 24a to which it connects than with the axis of the other suchflue. Such an offset ar rangement permits me to place the throats 24band the joints between such throats and the tube sheet 20 at a lowerlevel than would other wise be possible for the upper row of flues.

See Fig. 2. I am able, therefore, to lower the crown sheet 14 becausegood design requires a certain distance between the upper row of jointsin the sheet 20 and the crown sheet 14. The danger of damage to suchsheet due to low water is thereby considerably reduced.

The pairs of tubes 24a and their connected throats 24b can be easilyremoved from the barrel 10 when so desired through the usual manholes30, provided in the front flue sheet 22,

It will be seen that, when compared to a given design within the presentstate of the art, my invention permits a lowering of the height of crownwithout reducing evaporation appreciably or impairing the efficiency ofthe superheater.

This permits an increase in steam space and disengaging surface or adecrease in the weight of the boiler.

What I claim is:

A horizontal fire tube boiler having at least the top row of its tubesunited in pairs to common throats and each of said throats connectedinto a tube sheet, the points of bifurcation at which the pairs of tubesconnect to their throats lying nearer the tube sheet which is at thehotter ends of the tubes than to the other tube sheet and each throatcommon to a given pair having its axis off-set toward the axis of onetube of a pair and the axis of the throat lying nearer the axis of thelower tube of the pair than to the upper tube of such pair whereby thevertical height of the hotter tube sheet may be decreased for a givendistance between the upper openings in such tube sheet and its top edge.

